Introduction Anti-CD3 monoclonal Ab has been used successfully to revert diabetes in NOD mice, a murine model for Type I diabetes. Some laboratories are able to show up to an 80% correction of the hyperglycemia, while in our lab and other labs we are only able to show 40-50% correction rate. In humans, when anti-CD3 mAb is administered within 6 weeks of diagnosis of Type I DM, it decreases HbA1c and insulin requirement, but does not revert the diabetes. Exendin-4 is an analogue of GLP-1 which has been shown to increase neogenesis of beta cells and increase beta cell mass.

Anti-CD3 mAb and Exendin-4 in reversal of Type I DM in NOD mice Mariela Glandt Principal Investigator: Kevan Herold Columbia University

Aims To see if we can increase the percentage of mice that are euglycemic after treatment by combining antiCD3 mAb with exendin-4. To see if beta cell mass is higher when mice are treated with anti-CD3mAb and exendin-4 vs anti- CD3 alone To see if glucose levels are lower in mice treated with both anti-CD3 mAb and exendin-4, as compared to anti-CD3 alone

Methods NOD mice were monitored 3 times a week by urine dipstick until glucose was noted in urine. Glucose was then measured by tail venous sampling. When glucose was >200, they were treated with either anti- CD3 mAb only, anti-CD3mAb+ exendin-4, insulin only, or exendin-4 only. The mice’s sugars were followed biweekly by tail vein sampling. The mice underwent glucose tolerance test and were subsequently sacrificed at 3 weeks, 8 weeks, or 25 weeks The pancreases were fixed and stained for insulin and Ki67 Beta cell mass and replication rates were obtained by analysis using Image Pro software

Results 55 mice were treated with anti-CD3 mAb 29 mice were treated with anti-CD3 mAb + exendin-4 10 mice were treated with insulin only 4 mice were treated with exendin-4 only Glucose levels at start of treatment were similar in all 4 gps 45% of mice treated with anti-CD3 mAb reverted to euglycemia 72.4% of mice treated with anti-CD3 mAb and exendin-4 reverted to euglycemia none of the mice treated with insulin or exendin-4 alone reverted to euglycemia beta cell mass and neogenesis calculations are still under way

Success in reverting overt diabetes in NOD mice P=0.0222

Conclusions In NOD mice that have developed overt diabetes, treatment with anti-CD3 mAb and anti-CD3 mAb combined with exendin-4 results in reverting the disease. The success rate is higher when using anti-CD3 mAb with exendin-4, as opposed to using anti- CD3 mAb by itself. Analysis of beta cell mass, replication rates, and neogenesis is still under way to compare between the two groups